Robert Schoelkopf, director of the Marine Mammal Stranding Center, is worried that with every day that goes by, the dolphins are getting more comfortable in a place they cannot survive in for long.
The dolphins have been in either the Shrewsbury or the Navesink rivers in Monmouth County since early June, possibly as a result of a wrong turn chasing schools of bait fish along the coast.
"We want them to come up with some kind of plan as we approach the fall," Schoelkopf said Wednesday. "We don't want to be the bad guys again like in 1993, when four of them were in the river and they (federal officials) told us to leave them alone. Then the ice closed in on the river and four of them died.
"It's bad enough that happened with four, but now we have 15 to 20, and we don't want to have the same thing happen if they don't let us act until the last minute."
Teri Frady, a spokeswoman for the National Oceanic and Atmospheric Administration, which has jurisdiction over the animals, said they are fine where they are - for now.
"We're looking at all contingencies, including having to move them," she said. "But we're some time away from when we would worry about them."
The dolphins were last sighted near the Route 35 bridge over the Navesink River between Red Bank and Middletown on Monday, Schoelkopf said. Before that, they spent several weeks frolicking and feeding in the Shrewsbury River, which flows into the Navesink near Sea Bright and Rumson.
Schoelkopf said the bottlenose dolphins appeared to be in good health, aside from the fact that one of the babies appeared to be coughing over the July 4 weekend, possibly due to a parasite near his or her blow hole.
For now, the dolphins are feeding on fish in the two rivers, including mossbunkers, a fish commonly sold as crab bait.
"But that's the problem - the food doesn't stay there all year," Schoelkopf said.
The dolphins are only about a mile from Sandy Hook Bay, which leads to the ocean. In fact, researchers recently have spotted dolphins in the bay, but have been unable to tell if they are part of the group that was in the two rivers, or whether they are different animals, Schoelkopf said.
Schoelkopf's group recommends dangling acoustic pingers over the edge of boats, using the unpleasant noise to annoy the dolphins back out to the open water.
